The Zev Stainless Steel Guide Rod for Standard Frame Glock firearms (GROD-STD-SS) is an aftermarket part that replaces the factory OEM part.
Recommended usage of either an ISMI recoil spring in a corresponding correct weight for your pistol. In most cases 13 lbs fits best.
ZEV Guide Rods are NOT Compatible with Glock® Factory Guide Rod Springs.
If you plan to use this Guide rod with a Generation 4 model Glock® you must also use a Generation 4 reducer.